Vcarving Trouble

[TH]

I am losing steps in Z when V carving small parts, about 5"x5". I changed the VR settings to try and fix the problem. The toolpath runs smoother but it still misses steps. I attached a dial indicator to the router and ran the program and its about 0.120" above the part. I tried different speeds, from .5 to 2 in per second, and I matched the plunge and cut speed in Artcam as people suggest. I have looked thru many post and have modified my speeds and values to reflect there suggestions. Lots of good advice but I can't fix the issue.

I have checked the machine for play and it all seems fine. There is some backlash in all axis, between .005 and 0.008. I dropped the motors and checked the pinion gears, it all looks good, the pinions are all new except for the Z but its in good shape. Its a 25 tooth but I think it should be a 20. I have one and should put it it, more torque may help.

I ran a drill program with peck cycles for about an hour with the dial indicator installed in the router and it held the Z position within a 0.002".

The bot is a 2007 PRS Standard 48 x 96 with the 4G setup. I was looking for the ramp rates for this setup for vcarving and cutting 3d plus any other advice that could help.

Tom

[joe]

Why not show us what you're getting with a photo.

[TH]

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I attached a couple of images. I ran the program two times starting from the top of the block working my way down. I ran it several more times at the last elevation while changing the vr values to see If I could maintain Z height . I also missed steps in x or y, or both.

I also ran the program in air with the dial indicator with different speeds and vr values but always was hight in Z about 0.120".

[joe]

Ton,

gees, that's madening.

Do the errors occur in the same place each time? And is this happening only on this particular file? Surely there's some simple answer but this is a new one on me.

[TH]

-I just changed the pinion gear in the z to the 20 tooth, and updated the unit values.
-Adjusted the z roller bearings. Its the older type with 4 on each side, can only adjust the one side.
-I tried different places on the table and it repeats the error, 0.08" -.120" depending on what VR values I change. It cuts 2 fine.
-I have this shopbot for about 2 years and have not used it much. It's the first time I tried Vcarving anything but letters about an inch high.
-I have a bunch of relief files. As a test I programmed these in a YZ and XZ motion. I though it may help because it is mostly moving in only 2 axis. I ran in air with the dial indicator, same error in z. It may be in x and y as well.
-I am running an old labtop, with lost of junk installed, no internet. (I hope that is the issue)
-I checked the diagnostic information after each run and noticed the supply voltage was changing as much as 0.25V. The last time it varied from 0-5.24. I attached a screen shot. Is this a PC or a control box issue.
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[TH]

I posted yesterday but it did not update.

- I installed the 20 tooth pinion on the z axis and checked/adjusted the Z v bearings.

-The problem is repeatable at different locations on the table. I ran the UD after each program and noticed a supply voltage being as much as 0.25v difference. Is that a PC or the control box issue?
- I tried some 3d relief programs with raster cutting in xz then yz and there is a similar error in Z.
- I swapped geckodrive from Z to Y , no difference.
- Installed Shopbot on my design PC, no difference.
- Ajusted the geckodrive, no difference. (set pots back to original setting)
- When I had the cover off the controller the lights on the geckodrive dim while jogging 6"/sec, it that normal? One of the drives looks newer and the light is brighter.

NEXT STEP
- Swap out the Z motor with the Y.
- Run a ground from the Control box to the house ground.

Any thoughts?

Tom

[TH]

It's been a couple of weeks but I found a work around.

I uninstalled SB3.8.42 and installed SB3.6.46 for the older type control card, despite the fact I have a v212 card and V4G. It appears to work and maintain position. I have to search for the serial port each time I run the software. Once the port is found it's all good. I am not sure why it works or what the issue is with the original configuration cutting 3d. The problem is probably between the keyboard and my chair! Any thoughts?
Tom

[bobmoore]

What have you heard from tech support at shopbot. I would get them involved if I could as this is above my experience.

[TH]

-I have not contacted shopbot. When I upgraded from the explore card (about 2 years ago) SB told to run the latest version. No issues until I tried the smaller v carving and 3d reliefs.
-I will touch base with them.